Cashew's (Anacardium occidentale L.) production in Burkina Faso suffers from several biotic constraints. The aim of this study was to inventory the diseases associated with the tree. Cashew orchards were prospected in the production belt of Burkina Faso including Hauts Bassins, Cascades, South-Western and, Center-Western regions. Four major diseases were observed including anthracnose (Colletotrichum gloeosporioides), Pestalotia leaf spot (Pestalotia heterocornis), bacterial leaf and nut spot (Xanthomonas citri pv. anacardii), and gummosis (Lasiodiplodia theobromae). The incidence of the diseases varied according to the locations; in addition, anthracnose was the most spread disease with high incidence. Gummosis was observed in all the locations and was the second threat to cashew production in South-West and West Center regions. The bacterial disease which affects all parts of the cashew tree was mainly observed in the Hauts Bassins region. No virus was detected during this survey. Altogether, the results of this study represent an important baseline data for the design and implementation of strategies for cashew protection in Burkina Faso.

Prévalence du dessèchement du manguier et evaluation de la fréquence des champignons associés à la maladie au Burkina Faso. Objectif : l'objectif de l'étude est de contribuer au diagnostic du dessèchement du manguier au Burkina Faso. Il s'agit d'une part d'évaluer l'incidence et la sévérité de la maladie sur cinq variétés commerciales provenant du Dianda et al, J. Appl. Biosci. 2018 Prévalence du dessèchement du manguier et evaluation de fréquence des champignons associés à la maladie au Burkina Faso.

02/08 Fax : (226) 25 31 92 75 A B S T R A C T Cowpea (Vigna unguiculata (L.) Walp.) is one the main leguminous crop plants world wide, particularly in sub-Saharan Africa where the rainfall is low and often unevenly distributed. However, its production is limited by insect attacks and numerous diseases including those caused by viruses. In Burkina Faso, the Cowpea Aphid-Borne Mosaic Virus (CABMV) is one of the viruses capable of causing 7-60% of yield losses. The aim of this study is to assess the susceptibility of 21 cowpea varieties against CABMV and to also assess the yield losses caused by this virus on each of the varieties. In this context trial was conducted on INERA research stations at Kamboinsé and Farako-Bâ in 2012 and 2013. Twenty one varieties were used for this study. The experimental design used is a split-plot with 4 repetitions for which the first 2 repetitions were inoculated with the CABMV. Symptoms caused by the CABMV on the 21 varieties of cowpea were of a great diversity. The assessment of the virus in infected plant samples from these varieties by ELISA test allowed detecting the mosaic virus in all samples that presented mosaic symptoms. The number of flowers and pods strongly varied depending to the type of plant (inoculated or non-inoculated plant) and the variety. Yields from the different varieties, comprised between 187 and 6250 kg haG 1 , were influenced by the site, the year, the variety and the type of plant. Yields losses were ranged from 3-64% depending to the variety.

L’alternariose de la tomate est une maladie cryptogamique dévastatrice dans les zones maraichères du Burkina Faso. Tous les organes de la plante (tiges, feuilles, fruits) sont attaqués, entrainant une baisse importante du rendement et une dépréciation de la qualité de la production. Dans la présente étude, quatre huiles essentielles de plantes aromatiques locales (Cymbopogon schoenanthus, Lippia multiflora, Ocimum americanum, et Ocimum basilicum) ont été testées, pour évaluer leurs propriétés d'inhibition sur la croissance radiale du mycélium d’un isolat pathogène de Alternaria sp. Le test in vitro des doses de 100%, 50%, 10%, 5% et 1% a montré que toutes ces huiles essentielles possèdent une activité antifongique sur ledit isolat. Les taux d’inhibition des huiles essentielles sur la croissance du champignon étudié vont de 25,96% à 100%. La meilleure inhibition a été enregistrée avec l’huile essentielle de Cymbopogon schoenanthus, de Ocimum basilicum et de Lippia multiflora pour les concentrations supérieures à 1%. Il ressort donc de cette étude que trois huiles essentielles, stoppent la croissance mycélienne de l’isolat pour des doses allant de 5% à 100%. Ces huiles (Cymbopogon schoenanthus, Ocimum basilicum et Lippia multiflora) pourraient être utilisées pour la mise au point de phytopesticides afin d'atténuer l’utilisation intensive et hasardeuse des pesticides.Mots clés:  Alternariose, activité antifongique, plante aromatique, tomate. English Title: Effects of four essential oils on radial mycelial growth of an isolate of Alternaria sp. in Burkina Faso Early blight of tomato is a devastating cryptogamic disease in the vegetable gardens in Burkina Faso. All plant’s organs (stems, leaves, fruits) are attacked causing a significant decrease in the yield and a depreciation of the quality of the production in the field. In the present study, four essential oils of aromatic plants (Cymbopogon schoenanthus, Lippia multiflora, Ocimum americanum, and Ocimum basilicum) were tested to evaluate the inhibition properties of these oils on the radial growth of the mycelium of an isolated pathogen of Alternaria sp. In vitro tests at doses of 100%, 50%, 10%, 5% and 1% showed that all these essential oils tested have antifungal activity on said strain. The inhibition rates of essential oils on the growth of the fungus studied range from 25.96% to 100%. The best inhibition was recorded with the essential oil of Cymbopogon schoenanthus, Ocimum basilicum and Lippia multiflora for applied concentrations more than 1%. It therefore emerges from this study that three essential oils stop the mycelial growth of the isolate for doses ranging from 5% to 100%. These oils (Cymbopogon schoenanthus, Ocimum basilicum and Lippia multiflora) could be used for the development of phytopesticides in order to reduce the intensive and hazardous use of pesticides.Keywords: Early blight, antifungal activity, aromatic plant, tomato.  

Potyviruses are major constraints to grain legume production by causing significant yield losses. Potyviruses infecting Bambara groundnut (Vigna subterranea) were investigated in Burkina Faso. Leaf samples collected from three agroclimatic zones were subjected to RT-PCR and sequence analyses. Of a total of 135 samples, 36 (26.67%) were detected positive in RT-PCR tests using potyvirus universal primers. Analysis of full coat protein (cp) sequences from 24 isolates revealed the occurrence of three groups of Bambara groundnut-infecting potyviruses. Virus isolates in group 1 shared 94.5%-100% nucleotide (nt) identity with CABMV whereas those in group 2 and group 3 were distantly related Bean common necrosis virus (BCMNV) and Passiflora virus Ugandan which were their respective closest potyviruses. Group 2 shared 77.1% nt and 78.8%-79.9% aa identity with BCMNV and group 3 shared 77.3%-78.3% nt and 80.7%-81.5% aa identity with Passiflora virus Ugandan. All three groups were confirmed by phylogenetic analyses. Taking into account potyvirus demarcation criteria, group 1 isolates belonged to CABMV species. Group 2 and group 3 were assigned to a potentially new potyviruses species and designated Bambara groundnut potyvirus 1 (BGPV1) and Bambara groundnut potyvirus 2 (BGPV2).

Badnaviruses are serious plant pararetroviruses affecting banana and causes serious economic losses to banana production worldwide. This study aims to examine the variability of BSV and SCBV nature infecting banana in Burkina Faso. Polymerase Chain Reaction (PCR) used the Badna FP/RP specific primers for the RT/RNase H regions present in badnaviruses. The PCR yielded about 579 bp amplicons from banana infected by BSV and SCBV. The 38 BSV isolates recorded low nucleotide identity ranging from 58.9% -98.1%. Based on percentage nucleotide sequence identity and phylogenetic analyse, BSV isolates were categorized into four groups: 1, 2, 3 and 4. Group 4 shared 76.9% -100% identity with BSOL species. However, Groups 1 and 3 recorded a low identity ranging, from 76.8% -79.2%, 68.8% -79.7% with BSCV, and 72.8% -79.0% between Group 2 and BSOLV. Groups 1, 2 and 3 were assigned to a potentially new BSV species. The two SCBV isolates recorded a low nucleotide identity of 68% among themselves indicating high diversity. In addition, SCBV_Cd and SCBV_CE showed high nucleotide identity 91.3% and 58.7% with SCBV_C and SCBV, when they were compared to all published SCBV genotypes. In addition, phylogenetic analysis revealed the segregation of SCBV isolates into two genotypes, SCBV_Cd in C and SCBV_CE segregated in a new genotype namely Z. Recombination analyses showed weak signatures of recombination among some of the BSV and SCBV sequences.

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Imperata yellow mottle virus (IYMV, Sobemovirus) was first described in 2008 in the south-western region of Burkina Faso (West Africa). The genetic diversity of IYMV was not documented up to day. In this study, the variability of CP of IYMV was evaluated through the molecular characterization of 38 isolates collected in the western part of Burkina Faso. Comparison of sequences of these new isolates and one IYMV sequence available in GenBank revealed that the average nucleotide diversity was low. The ratio of non-synonymous over synonymous nucleotide substitutions per site was low, indicating a CP diversification under strong purifying selection. Despite of the low nucleotide diversity, phylogenetic analyses revealed segregation of IYMV isolates into six major clades. There was no correlation of phylogenetic grouping of isolates based on geographical location. This is the first study of the genetic diversity of IYMV.